1. Team 6 -...

2.  Spatially distributed deterministic models  Many hydrological phenomena vary spatially and temporally in accordance with the conservation laws of mass, energy and momentum. Such laws can be expressed as partial differential equations describing how the phenomenon of interest changes in space and time. Models based on conservation laws are also said to be physically- based.  Mass and momentum conserved

3.  Spatially Lumped models  Much simpler deterministic models can be obtained by aggregating or averaging the spatially variable processes to obtain a spatially lumped model. This is not usually done in a formal mathematical manner; rather, some simple assumptions are made which invariably start with a continuity equation.

4.  The model used should be a Distributed (hydraulic) model with Steady-state or Dynamic time

5.  From a computational standpoint, models in which space is represented explicitly will involve the solution of partial differential equations (PDEs) on a finite difference or finite element grid. Such models are therefore much more computationally demanding than lumped models, and they also require much more data to parameterize/calibrate them for a specific system.  It is therefore important that the model is matched to the application at hand; there is no justification in employing a complex, spatially distributed model when a simple model will suffice. Simpler models invariably have fewer parameters, and are easy to calibrate.

6.  Physically Distributed

7.  ????

8.  Can describe an observed (historical) precipitation event  Also a distributed runoff model for use with distributed precipitation data  Conceptual  Most of the models are lumped

9.  Model formulation  Deterministic therefore assumes boundary conditions, initial conditions and parameters are assumed to be exactly known – this is not always the case.  Programmes are uncoupled: evapotranspiration is computed and then infiltration, but in the real world the amount of evapotranspiration relies on the amount of soil water.  Therefore small time intervals for calculations should be used to minimise this error.  Flow representation  Does not allow for back water  No link between elements – downstream not linked to upstream  Diversion and reservoir elements are limited

10.  There are 5 rain gauges... Is this enough data to be able to distribute the rainfall well across the catchment or is it just as accurate to use a lumped model (it would be easier and quicker)  The discharge at the time of the flood was found by extrapolating the rating curve  the stage is continuously recorded throughout the flood event and then converted into discharge with a rating curve specific to that point in the river  However, the curve did not go high enough for the high water levels of the flood, so it was extrapolated  This means that we do not know if the observed discharge is correct/accurate